1. Field of the Invention
The present invention relates to image forming apparataus for forming images by means of a photo and pressure sensitive sheet formed by applying microcapsules in which a photocuring material, a dyestuff and the like are sealed on a carrier, and more particularly to means for treating an image receiving sheet after development.
2. Description of the Prior Art
For example, Japanese Patent Unexamined Publication Nos. SHO b 59-30537 and 64-29845 disclose a method comprising steps of uniformly dispersing and applying microcapsules in which a photocuring material, a dyestuff and like are sealed on a carrier to form a photo and pressure sensitive sheet, forming images on the photo and pressure sensitive sheet to be exposed and superposing the photo and pressure sensitive sheet on an imaage receiving sheet to form images. Typical ones of the photocuring materials comprise prepolymers of acrylic or metacrylic polymers, or their monomers and optional photopolymerization initators which can initiate polymerization by light.
When the photocuring materials are polymerized, the resulting resins are almost harmless. However, monomers are often harmful to a human body. By way of example, the monomers are irritative. If the monomers come in touch with a user's skin, a blister, an eruption or a rash often appears on the skin. Therefore, the monomers must be prevented from coming in touch with the human body. In a conventional image forming apparatus, the monomers flowed out of the microcapsules in pressure treatment remain on the image receiving sheet as they are and the image receiving sheet is discharged to the outside of the body. Therefore, there is a great risk that the monomers directly come in touch with the user'skin.
There has been also proposed a method in which the image receiving sheet is fully heated after the pressure treatment so that the monomers on the image receiving sheet are vaporized. In this case, however, a running cost for heating is increased and further the apparatus must be large-sized for high heating.